The present invention relates to apparatus and method for the launching and recovery of a sub-ordinate vehicle by a host vehicle and, more particularly, to the launching and recovery of unmanned vehicles or craft by host vehicles.
Various systems are known by which a host vehicle can recover another vehicle. For example and in the case of two spacecraft in a zero-g or near zero-g environment, both spacecraft are equipped with sensors for determining their respective alignments along the roll, pitch, and yaw axes and their respective velocities and accelerations along or about those axes. The two spacecraft are aligned along a common axis using computer-controlled thrusters and/or other attitude-control devices with one or both of the spacecraft advanced along that axis toward one another until the two spacecraft physically contact or engage. The two-spacecraft model is relatively simple, since the zero-g or near zero-g environment does not subject the spacecraft to difficult-to-predict and/or difficult-to-compensate-for external forces.
The situation is different in the area of aircraft and sea-going vehicles, including both surface and sub-surface vehicles, where the presence of surface and sub-surface currents, turbulence, wave action, wind effects, and the like complicate the problem of sub-ordinate vehicle recovery and launching. In an ideal situation, the sub-ordinate vehicle approaches and aligns itself with the docking interface of the host vehicle and, during that period when alignment is optimum or at least acceptable, pilots itself or is piloted into inter-active engagement. The presence of surface and/or sub-surface currents, turbulence, waves, and wind acting on the two vehicles oftentimes makes a sustained docking alignment difficult if not impossible to achieve.
Issues related to docking include addressing the mis-alignment along the roll, pitch, and yaw axes, and the changes thereof, consequent to the independent movement of the host vehicle and the sub-ordinate vehicle in three-dimensional space while the two vehicles approach and ‘close’ the distance therebetween.